Since most rear-end collisions of passenger vehicles happen at speeds of below 20 km/h, crash repair tests have been developed in the insurance sector with the aim of reducing damage in the case of typical rear-end collisions. By means of these tests, car insurances categorize passenger vehicles into type classes using the “AZT test”. Front end accidents of motor vehicles with a small lateral overlap are frequently associated with a greater risk of injury to the vehicle occupants than front end collisions over the full surface area. This is because, in the case of collisions with a small overlap, only the region next to the longitudinal members of the vehicle body is deformed, and therefore the longitudinal members, which are arranged next to the central longitudinal axis of the motor vehicle, can only inadequately support the load absorption, if at all. In these cases, the absorption of the collision energy leads to a high degree of deformation of the passenger cell, as a result of which there is an increased risk of injury to the vehicle occupants. Accordingly, in the design in particular of the front vehicle body, there is a need for improvement in respect of the load absorption in the event of front end collisions with a small lateral overlap.
In order to improve the energy absorption in the event of collisions with a small overlap, document JP 2004066932 A proposes expanding the longitudinal member laterally, wherein the lateral extension is also connected to the front crossmember. By this means, improved load absorption can be performed by means of the longitudinal member.
Starting from the above-described prior art, the invention is based on the object of specifying a vehicle body which ensures an improved load absorption in the event of collisions with a small overlap, wherein the deformation capability of the body is not substantially impaired in the event of collisions over a full surface area.
According to the invention, this object is achieved by a vehicle body mentioned at the beginning in that means for absorbing collision energy are provided for the at least one longitudinal member, said means ensuring that the load path is introduced into the at least one longitudinal member selectively in the event of a collision with a small overlap, wherein form-fitting means which form a form-fitting connection in the direction of the longitudinal member in the event of a collision are provided.
It has been recognized that the load absorption can be selectively increased in the event of collisions with a small overlap, and therefore the means according to the invention do not negatively influence the absorption of the collision energy in the event of collisions with full overlap of the at least one longitudinal member, in particular in the case of rear-end collisions of below 20 km/h. Owing to the fact that the improved load absorption takes place selectively, in the event of collisions with a small overlap, an increased load absorption can take place without putting the vehicle occupants at risk because of an excessive rigidity of the vehicle body in the region of the impact in the event of front end collisions in which the at least one longitudinal member already brings about an increased load absorption. In the event of collisions with a small lateral overlap, a reduction in the deformation of the passenger cell can be achieved by the means according to the invention, and therefore, in consequence, the protection of the vehicle occupants is increased. By means of the provision of form-fitting means which, in the event of a collision with a small overlap, form a form-fitting connection in the direction of the longitudinal member, the formation of the form-fitting connection is brought about by a deformation, in particular by the buckling of the crossmember in the region next to the longitudinal member and/or by deformation of the at least one longitudinal member. As a result, the deformation of the passenger cell can thus be further reduced and the protection of the vehicle occupants further increased in the event of collisions with a small overlap.
The form-fitting means may either be arranged on the at least one longitudinal member, but may also be at least partially arranged on the crossmember.
The crossmember provided according to the invention can be designed, for example, as a front or rear bumper. It is likewise conceivable for a vehicle body to have an arrangement according to the invention both in the front and in the rear region of the body.
The form-fitting means preferably have at least two connection partners.
According to a preferred refinement of the vehicle body according to the invention, at least one connection partner of the form-fitting means is designed as a wedge-shaped component. The wedge-shaped component may be arranged, for example, on the crossmember, but it may also be fastened to the at least one longitudinal member. The wedge-shaped component may be designed, for example, as a metal sheet or as a hollow profile. In addition to a design as a wedge-shaped component, it is likewise conceivable for a connection partner of the form-fitting means to be designed, for example, as a hollow profile with a polygonal, in particular rectangular, cross section.
Furthermore, the form-fitting means preferably have means for the form-fitting accommodation of the, for example, wedge-shaped component as the second connection partner. According to a particularly preferred embodiment, at least one connection partner of the form-fitting means is designed as a bolt-shaped component. In the event of a collision, the first connection partner, in particular the wedge-shaped component, can then be accommodated in a form-fitting manner by the bolt-shaped component. It is likewise conceivable for the form-fitting means to have different means as connection partners for accommodating the first connection partner, in particular the wedge-shaped component. For example, a recess or projection can be provided on the longitudinal member, which recess or projection is suitable for accommodating the wedge-shaped or differently designed first connection partner.
Alternatively or additionally, a tab-shaped component can be provided which is connected to the at least one longitudinal member and is suitable for accommodating the first connection partner. Particularly preferably, both a tab-shaped component and a recess or a projection can be arranged on the longitudinal member. It is accordingly also conceivable for the form-fitting means to have three connection partners.
The crossmember preferably has at least in regions an angle of smaller than 90° with respect to the longitudinal member. If said angled region is arranged on the outer edge of the crossmember, the load path can be particularly effectively introduced into the at least one longitudinal member in the event of a collision with a small overlap since the form-fitting means are moved in an intensified manner in the direction of the longitudinal member in the event of a collision.
The crossmember can optionally have a reinforcing plate for accommodating the form-fitting means, said reinforcing plate being arranged, for example, at an angle of smaller than 90° with respect to the at least one longitudinal member.
It is furthermore advantageous if the at least one longitudinal member has, in the connection region to the crossmember, a crashbox which can absorb collision energy by means of deformation in the event of a collision. The crashbox is connected to the at least one longitudinal member preferably by means of an integrally bonded or non-positive connection, particularly preferably by means of a screw connection.
According to a further advantageous refinement of the vehicle body according to the invention, the form-fitting means are connected to the crossmember and/or to the at least one longitudinal member in an integrally bonded manner, preferably by means of a welded, brazed or adhesive connection, and/or in a non-positive manner, preferably by means of a screw connection. In addition, it is conceivable for the form-fitting means to be at least partially integrally formed together with the at least one longitudinal member or the crossmember.
In a further advantageous refinement, at least one longitudinal member and/or the crossmember is composed of steel, preferably of a multiphase steel or an ultrahigh strength hot-forming steel. This is because the corresponding longitudinal member and/or crossmember then has particularly high strength, wherein a weight optimization of the longitudinal member and/or of the crossmember can be achieved at the same time. At least one form-fitting means is likewise advantageously composed of steel, preferably of a multiphase steel or an ultrahigh strength hot-forming steel.